Magenn

I hear you. Though:

My reference to an almost success was debunked bu wikipedia (Buckau). Even so, there are flettner ships in use apparently saving 25% fuel. (Saving 25% when you need to cut 100% is also a strange way of approaching global warming, but thats a different story). So it seems it’s enjoying some limited success and at least a lot of the hyped up prototype projects that you like so much…

Good article. Here’s the meat of it:
" The ship had proved inefficient on these voyages, with the power consumed by spinning 15m tall drums being greatly disproportionate to the propulsive effect when compared with conventional propellers. As the system could not compete economically, Flettner turned his attention to other projects and the rotors were removed.[8]"

This is saying you get less propulsion from the spinning sails than if you just put the same power into a regular propeller. If they worked well, you can bet Flettner would not have removed them from the ship.

And the section discussing “Saving 25%”, if you read carefully, is owned by a wind turbine company (Enercon) and they say “up to 25%” (compared to same-sized conventional freight vessels)"

That is two qualifiers to 25%. My guess is they are not counting the energy used to spin the cylinders, hence an illusion of “up to” 25%. Up to means “less than”, which could be only 5% or even zero or minus 5%!.

I’ll tell you what I think is going on here: In this climate of borderline insanity with people doing backflips to see who can appear to be the most politically-correct and carbon neutral, people are doing whatever it takes to have even the appearance of “making a difference”. It’s not the actual making of a difference that counts, since few people can figure out whether they actually ARE making a difference, but the emotion-based illusion of making this “difference”.

If faced with the facts, the politically-correct rationale is typically “Well, we’re raising awareness”. So, as we often see, even projects that end up using MORE fossil fuels are lauded and worshipped, as long as they look like they might use slightly less fuel. And after spending all that money to create this illusion, the companies know better than to tell people it doesn’t really save any fuel. They just pull out a figure indicting some minor savings and then quickly change the subject. It’s more about illusion, emotion, and public relations than anything else.
Did you know people have built a wind turbine using flettner rotors as blades? Yup, they apparently must have sucked too. Not that sucking is a bad thing for an airfoil,since that is how they work, but, well, you know what I mean. :slight_smile:

There are significant differences between Flettner rotors used for vessels and that for AWES, as the first are appropriate only for some wind directions and undergo the cantilever effect while the second can be inflatable, are held by both ends, and face the wind. So different results can be expected. But the power consumed is comparable and can be very high for too high spin ratios. For AWES a spin ratio of 2, perhaps 3, could be a limit.

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As a comment to what you are saying about creating an illusion of being environmentally friendly: The Norwegian state just awarded $260 mill to AN OIL COMPANY to create (not install, but actually develop new tech) windmills. These windmills will supply power to OIL PLATFORMS for the next decades.

We are doomed as a species.

(Let me just state that this is a satirical post. Though my general opinion should be clear, the actual decision about this funding is a complex one, and I’m sure it was done with only the best intentions)

If it produces usable power at a good price, better than burning even more fuel.
Hywind uses the ballast-stabilized spar-buoy floating wind turbine foundation that I invented. See Figs. 14-20 of my Euro Patent:
https://patents.google.com/patent/EP1407139B1/en
Do you realize the oil industry controls the environmental movement? It keeps them in a monopoly position by restricting drilling, otherwise oil would be so cheap nobody could make a profit. They also control politics - watch the financial channel where they talk bout how the only reason oil prices haven’t collapsed is Venezuela and Iran, two of the largest producers, have been shut down via a revolution and sanctions. Coincidence?
Tallak you have to realize something my grandmother once told me:
There is ALWAYS, and has always been, a doomsday scenario being promoted, always looming in the background, but it never actually happens, so stop worrying. For all you know, the carbon is staving off another glacial cycle. It’s a known fact the planet is now greener than it was a few decades ago, from satellite photos. When I was a kid, it was 1) nuclear war, and 2) overpopulation (we were not supposed to be able to grow enough food for more people). They had us hiding under our desks at school. Today the doomsday scenario is all about temperature. They depend on kids like you going into panic-mode, since you haven’t already been through ten previous “we’re all gonna die!” scenarios yet… Give it a few years and it will be all about robots, disease, mosquitos, meteors, drones, or something else - maybe even cooling. I know, you laugh, but just wait and see. What I’m more concerned about is spending my life inventing wind turbines and having a major developer using the idea I paid to develop and have published. We’ve had a patent issued in the U.S. based on the documented fact I invented the only floating wind turbine foundation in commercial use today, U.S. Patent 10,024,307 Floating Marine Wind Turbine. Currently looking to sell the patent. We’re auctioning off the deepwater offshore locations in California next year. If you know any decision-makers at Equinor, please have them contact me.

I just ran across this patent to stow a shipboard flettner / magnus rotor.
The problem?
The tall cylinder causes air drag when not in use, slowing the vessel and/or causing more fuel to be burned. The promoters of the magnus sails don’t say anything about the extra weight of not only the cylinders, but the weight of the rotary support structure, which must be strong enough to survive storms, the weight of the drive motors with gearing, and the weight and expense of whatever setup is required to provide the power to run the drive motors.
Why don’t we see any ship trying simple (regular) sails, even in a limited way? My guess? Regular sails would seem like giant step backwards. Sails are old-news, and sound boring, with no “Professor crackpot” sexiness from which to generate exciting “look how green we are” press-releases. Nonetheless, I’ve always wondered why oceangoing ships do not have auxiliary sails. Regular sails require no significant power to operate, weigh less, and are easier to stow away for storms or times of no wind, and when stowed would cause no drag. When I saw the fact that these cylinders actually slow the vessel by causing air drag when there is no wind, I realized that weighs strongly against their wide adoption. More fake-future-news, being promoted by people with the very best of intentions, is my best guess. As with kite-ships, probably better proven as advantageous in small craft before getting too far into convincing ship operators to spend millions of dollars with these “raising awareness” symbolic projects destined to be quietly dismantled like Flettner’s original rotor-sail demo ship, once the hype has served its purpose. If someone truly has a better way to sail a boat, I say prove it in the existing field of sailboats and sailing, maybe show you can win some races, or go home.
:slight_smile:

Very good points… Flettner may be a dead end for ships…

Wrt doomsday scenarios: In the 80s we had acid rain, and no doubt it did considerable damage to ecosystems here in Norway. Humanity managed to deal with that one. But it was looking quite bleak for Norway at one point. These are facts, we must not just forget that there was real chance of doing substantial damage here.

Now we have global warming. Though I would very much like to take the «happy go lucky» stance you do, and as I respect that you have come to different conclusions on the severeness, for me i see both good and very bad outcomes of this. Both are possible. The odds of the bad one coming true is way too high, and people are showing a fantastic inability to act on the problem.

So when (if) the bad outcome is real, we can look back at how the Norwegian government «saved» us by giving money to the oil companies so they could extract oil more cheaply…

Sorry for going off topic. We might start a new thread on global warming, but it’s better I think to stick to AWE, much more interesting

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Here’s that patent I mentioned:
https://patents.google.com/patent/WO2011103870A3/en

Let’s see, we were supposed to panic over global cooling in the 1980’s. That culminated when combined with mandatory panic over nukes, resulting in the highly-acclaimed documentary “The Day After”, where the world froze in response to a nuclear war. Meanwhile, we were also all gonna die from AIDS, another human-caused problem. For the next 30 years, every time I’d mention dating another girl, my mother would caution me against getting AIDS. No matter how many times I told her guys can’t get AIDS from girls, she was working from emotion and propaganda, not facts. More recently the stock market collapsed one fine day when panic over “Ebola” hit the airwaves. A few days later, it recovered. Life went on as usual.
Acid rain? Well I used to climb the very mountains and collect plants for terrariums from the very mountaintop swamps (yes I did say mountaintop swamps) the acid-rain-panic promoters mentioned, and knew very well the soil and standing water were NATURALLY highly-acidic. Therefore I saw the acid-rain panic for what it was. It was years later that I saw such a simple fact acknowledged, as the whole “we’re all gonna die from acid-rain” panic silently “went away”. Now I know it may be difficult to break through the particular doomsday “programming” your generation has been subjected to, but it’s nothing new, as my grandmother, born in 1899, explained to me as a kid. Now I’m kindly passing that same wisdom along to you. You’ve expressed dismay about why older people (more life experience) tend to somewhat scoff at “mandatory panic” over temperatures. Well all I can say is, wait a few years and you will slowly wake up and by the time you’re my age, be saying the same thing to some younger person panicking over whatever “we’re all gonna die!” mandatory-panic scenario is being floated by “the power of suggestion” to the next generation, likely to control access to resources, just as it is today. It’s not a matter of ignoring reality in a happy-go-lucky dream-world, it’s a matter of “been there, done that”, seeing one more “Boy Who Cried Wolf” call for mandatory panic and laughing because you’ve already been through ten other calls for mandatory panic and you finally recognize the pattern. A similar pattern is seen in the world of advertising. Advertising targets people below a certain age range, because it’s been found that once you reach a certain age, you no longer respond to advertising, since you’ve seen so many ads you finally see the pattern and just ignore the ads and think for yourself.

Except you havent been to global warming. You can conclude that people will react in a certain way to an issue. But it would be unwise to think that because acid rain was ok, then global warming is ok too.

Acid rain was an example. Of course acid rain is only dangerous for wildlife in freshwaters. Noone ever thought acid rain would be the end of humanity. Nor AIDS. And AIDS can transfer from female to male as far as I know. But many people think global warming could at least cause a major worldwide crisis

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I forgot to mention so many dire doomsday scenarios. One was what we students at UC Irvine laughingly called “the ozone hoax”. (Ozone hole). I walked by Sherwood Rowland’s lab where they “discovered” it every day. Just as you had to climb the highest mountains in New York State to find the (naturally occurring) acid swamps with their carnivorous pitcher-plants and other interesting flora (which can only survive due to the extreme acidity), you had to fly into the Antarctic stratosphere to find a place where the ozone (formed by sunlight) decreased during winter. Not that you wouldn’t expect a chemical caused by warmth and sunlight to decrease during an antarctic winter, but they nonetheless sold the world on switching to the new version of Freon based on a very dubious doomsday scenario. Another was DDT - there was a book called “Silent Spring” that complained egg shells were getting too thin, due to DDT. What many people do not get is that every one of these issues has an unstated agenda. The ozone thing happened just as DuPont’s patents on Freon were expiring and of course they had a newly-patented version which begged for some way to outlaw the old Freon and prevent its production as a generic commodity, forcing people to buy the new one that was ten times as expensive. Some say the further hidden agenda was to keep the third world from enjoying cheap refrigeration and air conditioning, lest they advance too fast, without a U.S.-owned Starbucks and McDonalds on every corner. Same thing with DDT - mosquitoes and malaria were the only things holding certain populations in check. Free access to DDT could have caused a huge population explosion in regions where people were already so overcrowded and undeveloped they were living in their own sewage. Acid rain? It forced new powerplants to be built, putting old plants out of business, opening the opportunity for better-funded power companies to force the smaller players into bankruptcy. The Exxon Valdez oil spill? It resulted in old tankers being outlawed so only highly-funded carriers with new double-hull tankers could stay in business. The Deepwater Horizon oil spill? How convenient: It allowed the president to outlaw offshore drilling just as the great recession took hold, preventing a collapse in oil prices. None of this stuff is what it looks like. Think of it all as a scripted play, where the ending is already known by a very few, experienced as a naturally-unfolding, spontaneous series of seemingly unconnected events by almost everyone except those in the know and those who pay attention. Like I said, never easy to debunk the religion of a true-believer, but someday you may find yourself explaining it to the next generation after you. Why do I like wind energy? Cuz it’s free (sort of) and it’s fun! Solar is also free(ish) but boring. It just sits there working, with nothing to go wrong. There are no “idiots”, no “crackpots” to harass in solar, just a bunch of boring silicon sheets. wa-wa-wah… :slight_smile:

Well, to be the one using the «professor crackpot» meme, its strange to see you spreading conspiracy theories.

This pretty much sums up what I think of your previous post: http://www.math.ucr.edu/home/baez/physics/General/occam.html

Roads only get improved by the council after enough citizens have had accidents in a particular place. Nowadays the contractor has a better road building solution than 2 old guys with a shovel.

@dougselsam acid rain was a real problem and continues to be addressed, nuclear problems are real and need continually addressed, viruses are real, people work on them every day…

Yes it’s good to be able to see patterns of development. (Look too at generational perception shift. e.g. What was a tiddler fish is now considered a whopper … We have overfishing problems. Which need addressing)
But we also need to maintain a perspective of our own thinking… Try googling research on “People who believe 1 conspiracy theory also…”

I’m delighted you work in airborne wind energy. Your designs are pure quality! But you are a funny bonkers old nutter. Don’t change.

Hi Roddy:
Don;t get me started on bad roads. Seems like the most heavily-taxed states haave the worst roads. The more they collect, the less they spend on the stuff normal people depend on, like smooth roads. Anyway…
That term you used was cooked up then heavily promoted as part of a well-known coverup of yesteryear…
So basically it’s a response you’ve been trained to say. A script. Planted in your head. Congratulations.
Some people just see things that the average person does not.
All of these issues were in fact presented as dire, end-of-world scenarios.
Take the very limited information I mentioned as you will.
It’s apparently not for everyone to understand certain things.
I share your concern with overfishing, by the way.
In fact I have a saying:
Give a man a fish and he will eat for a day. Teach a man how to fish, and he will teach smeone else, and soon there will be no fish left in the ocean.”
See Roddy? I think for myself. See how that works?
Think about the big picture though:
Most of those great fishing areas were dry land a few thousand years ago.
There are still trees down there. You’d have been hunting, not fishing.
And to think we just enjoyed some Northern Atlantic Cod at last night’s Friday fish fry.
Twice as much as I could eat.
I keep thinking: “They still have enough Cod to catch in the North Atlantic?”
Well think about it: If all those areas were dry land during the ice age, you can thank 11,000 years of ongoing global warming for the original abundance of fish. But that abundance of fish is not “normal” for the last 2 million years. It only happens during the brief glacial minimums such as we enjoy today. Then it gets cold again… The oceans become drained. Your island becomes part of the mainland.
Atlantic Cod: Better than eating out of the Pacific (Fukushima).
And Fukushima is an example of what I was saying bout nukes being great as long as you can guarantee people will be smart enough to handle it, which they often are not already. Who in their right mind would located a nuke plant in a known Tsunami area??? Then again, who knows what unspoken sunken nuclear accidents are lurking in the Atlantic?
Most people these days are eating “Tilapia”: translation: fish grown in backyard tanks in China, fed God-knows-what. I think I heard it is sometimes pig feces or something. I wouldn’t touch it.

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I can remain certain that the standard of our local fisheries is maintained and that our government is doing all it can to protect the situation…


Talking of fish and polution… (What has this got to do with Magenn?)
The harbour charges fishing boats to take their rubbish but doesn’t count what a fishing boat takes aboard… So Basically they charge fishing boats if they don’t dump their rubbish at sea. GREAT!

A vertical trajectory is also possible when it is far from the winch in order to allow the Magnus rotor taking speed. This is shown on the chapter 13 (Optimization-Inspired Control Strategy for a Magnus Effect-Based Airborne Wind Energy System) of the AWE book 2018:


A preview of an extract is available on

You mean a vertical trajectory while the kite is placed downwind? This is of course crosswind, though the kite would fly to the edge of the window quite quickly…

Yes. It is the reason why a long tether allows the Magnus rotor to take more speed longer. It is less efficient (x 2 less according to the evaluations given par A. Hably’s different papers for both) than figure-eight, but the management can be simpler, and the land use lesser.

The problem with crosswind flight for a Magnus rotor is the power consumption to spin the rotor. Indeed the tangential speed³ is the wind speed X the glide number (lift to drag ratio as simplification, generally between 2 and 3 for a high spin ratio) of the Magnus wing (that to obtain the apparent wind) X the spin ratio.

An example with 10 m/s wind speed, for a Magnus rotor of 1 m², spin ratio of 2, Lift coefficient of 3.8, drag coefficient of 1.5 (according to the figures 4 and 7 of the paper Experiments on a Flettner rotor at critical and supercritical Reynolds numbers).

Power consumption (equation (3)) : 0.007 X 1 X 3.14 X 1.2/2 X 50.6³ = 1708 W.
Power harnessed: 2/27 X 1.2 X 1 X 1000 X 3.8 X (2.53)² = 2162 W before losses by cosine and by mass @tallakt includes in his calculations.

So it appears that for a Magnus rotor the higher apparent wind due to crosswind flight is the killer in regard to the required power consumption.

https://www.researchgate.net/publication/333600036_Magnus_Based_Airborne_Wind_Energy_Systems/comments is a question I asked about the power consumption.

The equation (3) of Experiments on a Flettner rotor at critical and supercritical Reynolds numbers assumes that the tangential speed of the Magnus rotor is cubed, while the equation (5/18) on https://www.researchgate.net/publication/332799296_Airborne_wind_energy_system_Control_and_experimentation and the equation (12.21) page 293, chapter 12 of
Airborne Wind Energy - Advances in Technology Development and Research consider that only the wind speed is cubed, the spin ratio X being not cubed. This would lead to huge differences.

As an example wind speed = 10 m/s, and spin ratio X = 4, all other parameters being equal.

By the equation (5.18) the power consumption is …4000…

By the equation (3) the power consumption is …64000…

@tallakt and me used the equation (3) in this topic. I think equation (3) leads to results that are closer to the experienced reality (Omnidea on https://collegerama.tudelft.nl/Mediasite/Play/e51a679525fe491990de3a55a912f79d1d as an example, and also some historical literature).

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